Comet

Grab your binoculars to catch a glimpse of speedy Comet C/2018 Y1 Iwamoto over the coming week before the glare from a full Moon on 19 February drowns it out. Potentially attaining magnitude +6, the comet passes closest to Earth on 12 February when it can be found traversing Leo at a rate of 7.2 degrees/day. Don’t miss C/2018 Y1’s close enounter with galaxy NGC 2903 on 13 February – by eye, camera, or live online.

Bright Comet 46P/Wirtanen skims past Earth just 30 lunar distances away on 16 December when it could become a diffuse magnitude +3 object almost a degree wide located between the Pleiades and Aldebaran in the constellation of Taurus. Grab your binoculars and find a dark sky location well away from streetlights to enjoy this Christmas comet before the glow from a waxing Moon gets too bright from 17 December.

ESA’s Rosetta spacecraft observed unusual jets of gas and dust spewing from comet 67P/Churyumov-Gerasimenko every morning as the sun came up. A new study shows those jets formed as a result of the comet’s strange topography.

Despite the glow of a waxing Moon, early April is a good time to catch a glimpse of comets 41P/Tuttle–Giacobini–Kresák and C/2015 V2 (Johnson) that are currently circumpolar and visible throughout the UK hours of darkness. And if you’re an early riser, there’s seventh-magnitude C/2017 E4 (Lovejoy) low in the pre-dawn eastern sky too!

Comet 45P/Honda–Mrkos–Pajdušáková passes just 0.08318 astronomical units (7.73 million miles, or ~32 lunar distances) from Earth on the morning of 11 February. Early risers can catch the magnitude +7 comet speeding through the constellations of Hercules, Corona Borealis (CrB) and Boötes at up to 9 degrees/day.

Amateur and professional astronomers are invited to provide observations of comets 41P/Tuttle-Giacobini-Kresák, 45P/Honda-Mrkos-Pajdušáková, and 46P/Wirtanen that will pass by Earth at distances ranging from 0.08 to 0.15 astronomical units. Such close approaches of a trio of comets within the next two years are rare and typically occur only once every few decades.

Based on computer simulations, astrophysicists at the University of Bern conclude that comet 67P/Churyumov–Gerasimenko did not obtain its duck-like form during the formation of our solar system 4.5 billion years ago. Although it does contain primordial material, they are able to show that the comet in its present form is hardly more than a billion years old.

Canadian researchers have charted a path that most likely pinpoints the very origins of 67P/Churyumov-Gerasimenko, the comet studied intensively by ESA’s Rosetta spacecraft. Western University astronomers believe that 67P is made from primordial material and relatively new to the inner parts of our solar system, having only arrived about 10,000 years ago.

A comet strike may have triggered the Paleocene-Eocene Thermal Maximum (PETM), a rapid warming of the Earth caused by an accumulation of atmospheric carbon dioxide 56 million years ago. Atmospheric carbon dioxide increased rapidly during the PETM, and an accompanying spike in global temperatures of about 5 to 8 °C lasted for about 150,000 years.

The sharpest, most detailed observations of a comet breaking apart have been captured with the NASA/ESA Hubble Space Telescope. The images suggest that the roughly 4.5-billion-year-old comet, named 332P/Ikeya-Murakami, may be spinning so fast that material is ejected from its surface. The resulting debris is now scattered along a 3,000-mile-long trail.